This illustration shows three large desktop computers arranged in a triangle, with the computer at the top point of the triangle labeled "Super peer." Each large computer is connected to four smaller computers. In the cluster of computers at the top of the triangle, one of the small computers is labeled "Callee peer." In the cluster on the right side of the triangle, one of the computers is labeled "Relay peer." And in the left cluster, one is labeled "Caller peer." A blue arrow extends from the Callee peer and through the Relay peer to the Caller peer.